Omega Owners Forum
Omega Help Area => Omega General Help => Topic started by: mtbskills on 10 February 2010, 09:45:48
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Bit disappointed with performance for a big (ish) v6, mainly lack of low down torque
Seems very flat below 3000rpm, better above that.
Multirams are operating (visually while revving engine), slight blow on centre section of exhaust.
Usually drive a D5 diesel volvo, which has loads of low down torque, so am I expecting too much
or can anyone suggest what to check next ... cant afford to replace exhaust yet :(
Thanks :y
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It might be just down to the differing characteristics of petrol and diesel engines.
Diesels produce more torque lower down the rev range, petrol engines produce their main power higher up.
Having said that it might be worth checking some basics like the air filter (also check the air intake system for any other obstructions) and the spark plugs.
Do you have the service history for the car? When was it last serviced?
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No real history unfortunately, but just did the filters, fluids, plugs etc myself, so should be somewhere near good !
I'll try a vacuum system check next, might be leaking somewhere :y
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Is your V6 auto or manual?
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Bit disappointed with performance for a big (ish) v6, mainly lack of low down torque
Seems very flat below 3000rpm, better above that.
Multirams are operating (visually while revving engine), slight blow on centre section of exhaust.
Usually drive a D5 diesel volvo, which has loads of low down torque, so am I expecting too much
or can anyone suggest what to check next ... cant afford to replace exhaust yet :(
Thanks :y
gets even better above 4500rpm
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I used to feel that my last Omega (manual 1994 2.5 V6) was gutless.
I recently switched to an automatic 2003 2.6 V6. Despite being auto it feels quite a lot stronger than the 2.5 did.
I changed the cambelt myself 3 times on the 2.5 but I didn't realise then that there was a special crank locking tool that I should have used. I am now curious as to whether performance would have been improved if I had used one :-/
The time has arrived to fit a new cam belt kit to my 2.6 so I need to get my hands on the cam/crank locking tool first.
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I am curious as to how you were lucky enough not to have 24 bent valves. :o ::)
But yes, if the cam timing was a tooth or two out on each cam it would affect performance and economy quite badly. :y
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I am curious as to how you were lucky enough not to have 24 bent valves. :o ::)
But yes, if the cam timing was a tooth or two out on each cam it would affect performance and economy quite badly. :y
Give me some credit....
I have the cam locks, the cam belts come with markings that correspond with the marks on the pulleys and there are marks on the oil pump and cam cover backplate.
I also have the Haynes book of creative writing.....
With the tools available (& Tippex ;)) I checked and rechecked the alignment. If the cam timing was inaccurate then it would have been due to innacurracy in the timing marks on the backplate.
I drove 70,000 miles in that car so I must have got the cam timing fairly close.
I did spend a long time checking the alignment. Strikes me that the time saved and the repeatabilty achieved using the crank locking tool & spectacles is reason enough to justify buying them. More accurate cam timing would be a bonus :y
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Its a manual, 120000 miles recorded ::)
perhaps its just me becoming a lazy diesel driver then !
Strange thing happened last night, tried to start it from (very)cold, turning over fine but not catching, BUT, regular "thump" from engine as it turned over
Happened 3 times, took key out, back in then started perfect !
Any ideas ? Running ok now, fingers crossed :)
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do a paperclip test mate :y
guide in the maintenence section
see if they is any codes stored and then post them on here
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will do, thanks. this weekend most prob
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right then, did the code test, only stored code was 31, but engine wasn't running so
this is normal ?
had the starting thing again, turning over with no sign of catching, then started fine after key out/ back in.
Immobiliser maybe ? Saying that, does it have one as standard ?
Your insight would be welcome :y
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Immobiliser is standard. On my very early (1994) V6 the immobiliser prevented the starter from turning. Don't know if it was different by 98 :-/
I think 31 is 'no RPM' so normal if the engine not running.
I did have a crank sensor fail which didn't bring up any code (other than 31) but that didn't cause a gradual power loss, it just refused to start outside the office (but did start after the AA had towed me the 10 miles home).
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just checked the codes, definitely no rpm so thats ok :)
lots of posts on here about the crank sensor failing on these, might be worth doing anyway.
did you change yours yourself, andy ?
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just read the maintenance guide for the crank sensor, looks easy enough :P
this is one helpful site !
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did you change yours yourself, andy ?
I did :y
I would recommend that you get your front wheels up on ramps so that you can get underneath the car to get at the crank sensor.
I can't remember whether I took the scuttle off to gain access from above as well :-/.
I don't know that you actually have a failing crank sensor but given their tendency to fail when least convenient it makes a lot of sense to get a spare.
There are two types of sensor, one has an oval plug, the other has a rectangular one.
If you don't already have some then get a set of Torx/star bits because you will need one to undo the sensor retaining bolt (can't remember the size).
HTH
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The sensors don't fail that often .. but the cables to them do ! They run VERY close to the exhaust and get overheated.
Guide suggests ignoring the original path and rerouting the cable well clear of the exhaust.
Scuttle off make it much easier. The "clip" the connector goes into can be a bit fiddly to undo.
Jack up passsenger side, stick it on an axle stand and with the passenger side front wheel off you have plenty of room to get to the sensor bolt.
HTH
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Hi,
don´t know if this will help. I had exactly the same problem on my 94. 2.5 Omega - lack of power and later on bad starts (first try no success, but then it started ok). I have found two problems - bad EGR valve and leaking fuel pipe (the one from engine back to tank). Due to leaking pipe the fuel system lost pressure and so the bad starts (and also very bad consumption). I haven´t tried it after the repair yet, so I do not know if the power will be better (I have bought 3.0 and the difference is HUGE :) )
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Thanks for the advice all :y
Update ! did some more work this weekend, flushed and bled brake system, changed drop links, rotated tyres, and found a split in a vac hose which had been taped up previously,
Retaped hose as temp measure, and seems a little better, but may be wishful thinking
BUT.... noticed a coolant leak from passenger side of engine, down on the block somewhere ::)
didnt have time to locate properly, but HBV seems a good guess from posts on here ! Is it located here ?
And... very strange knocking from top end somewhere during warm up. Its ok when cold, gets very noisy when engine around 20 - 40 degrees , then fades to almost nothing when up to temp !
Sounds too Heavy to be tappets, and cam bearings would be noisy all th time I think ? Any ideas welcome .... this is turning into a nightmare !
Oh, and have ordered a crank sensor just in case :D
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Firstly, 31 can be ignored IF the car starts. If the crank sensor is dead enough to cause a 31, it will never, ever start.
Obviously, and diesel will feel more torquey than any petrol, thats the nature of the beast.
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Thanks for the advice all :y
Update ! did some more work this weekend, flushed and bled brake system, changed drop links, rotated tyres, and found a split in a vac hose which had been taped up previously,
Retaped hose as temp measure, and seems a little better, but may be wishful thinking
BUT.... noticed a coolant leak from passenger side of engine, down on the block somewhere ::)
didnt have time to locate properly, but HBV seems a good guess from posts on here ! Is it located here ?
And... very strange knocking from top end somewhere during warm up. Its ok when cold, gets very noisy when engine around 20 - 40 degrees , then fades to almost nothing when up to temp !
Sounds too Heavy to be tappets, and cam bearings would be noisy all th time I think ? Any ideas welcome .... this is turning into a nightmare !
Oh, and have ordered a crank sensor just in case :D
HBV is located at the back of the engine looking from the front of the car. It is actually under the black windscreen scuttle (bit where the wiper arms come out of).
Your "engine block" leak might be a core plug. If the car hasn't had antifreeze in they can fail. Have you got a stain down to and below the oil filter on the side of the engine?
Another problem area on the vacuum system is the vacuum tank. That is located low down on the left of side of the rad when standing at front of car. I have a similar gutless problem with my car and as yet have failed to find the prob though I too have found split pipes (at rear of plenum). As ever the advice is to be methodical and test rather than just keep buying new parts in the hope of fixing.
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HBV is located at the back of the engine looking from the front of the car. It is actually under the black windscreen scuttle (bit where the wiper arms come out of).
HBV is at the back of the driver's side of the block. :y
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HBV is located at the Another problem area on the vacuum system is the vacuum tank. That is located low down on the left of side of the rad when standing at front of car. ....
A car of your age should have 2 vacuum reservoirs. One where you say, by the rad, the other should be next to your pollen filter ;)
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HBV is located at the back of the engine looking from the front of the car. It is actually under the black windscreen scuttle (bit where the wiper arms come out of).
HBV is at the back of the driver's side of the block. :y
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HBV is located at the Another problem area on the vacuum system is the vacuum tank. That is located low down on the left of side of the rad when standing at front of car. ....
A car of your age should have 2 vacuum reservoirs. One where you say, by the rad, the other should be next to your pollen filter ;)
If my late 97 car (which is a "98 mini facelift") has a second reservoir I have never seen it. Is it under the scuttle next to the pollen filter or in the engine bay next to the pollen filter?
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HBV is located at the back of the engine looking from the front of the car. It is actually under the black windscreen scuttle (bit where the wiper arms come out of).
HBV is at the back of the driver's side of the block. :y
....
HBV is located at the Another problem area on the vacuum system is the vacuum tank. That is located low down on the left of side of the rad when standing at front of car. ....
A car of your age should have 2 vacuum reservoirs. One where you say, by the rad, the other should be next to your pollen filter ;)
If my late 97 car (which is a "98 mini facelift") has a second reservoir I have never seen it. Is it under the scuttle next to the pollen filter or in the engine bay next to the pollen filter?
under the scuttle next to the pollen filter :y
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doesnt seem like the hbv then
i dont know for sure if the leak is from the block itself, could be a hose or joint down there somewhere.
any ideas on the 'orrible noise ? or should i post another thread for that one ?
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Firstly, 31 can be ignored IF the car starts. If the crank sensor is dead enough to cause a 31, it will never, ever start.
Obviously, and diesel will feel more torquey than any petrol, thats the nature of the beast.
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but you would expect a 2.5 v6 to pull reasonably well from low down ? all my previous petrols have been 4 pots, so not got much to compare with really